(1) Field of the Invention
This invention relates to hot tops as used in conjunction with ingot moulds to form a heat insulating and heat adding extension at the top of the ingot mould which serves to retain a bath of molten metal in the top of the mould during the solidification of the ingot poured therein. The effect of such an action is to prevent or minimize piping and formation of other defects in the ingot being poured as it cools.
(2) Description of the Prior Art
Prior hot tops have relied on a series of panels of equal length hinged to one another in a chain-like configuration. See for example U.S. Pat. Nos. 2,361,386, 3,468,368 and 3,836,112.
In U.S. Pat. No. 2,361,386, a series of separate panels are linked to one another. In the present invention, two pairs of two distinctly different panels form an expandable endless belt-like structure.
U.S. Pat. No. 3,468,368 discloses a multiple panel assembly fastened together which can be arranged to form a hot top for insertion into an ingot mould. In the present invention, an inwardly folding expandable hot top is disclosed and arranged for mechanical expansion within an ingot mould for sealing relation with the mould.
In U.S. Pat. No. 3,836,112, a flat folded hot topping assembly is described wherein two hinged sections of material are each scored midway from either end. In the present invention, six panels are hinged to one another to provide an outwardly expandable accordiontype folding action to shape and position the hot top thus formed.